J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1994-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.tools.tree; |
| 27 | |
| 28 | import sun.tools.java.*; |
| 29 | import sun.tools.asm.Assembler; |
| 30 | import sun.tools.asm.Label; |
| 31 | import java.util.Hashtable; |
| 32 | |
| 33 | /** |
| 34 | * WARNING: The contents of this source file are not part of any |
| 35 | * supported API. Code that depends on them does so at its own risk: |
| 36 | * they are subject to change or removal without notice. |
| 37 | */ |
| 38 | public |
| 39 | class NotExpression extends UnaryExpression { |
| 40 | /** |
| 41 | * Constructor |
| 42 | */ |
| 43 | public NotExpression(long where, Expression right) { |
| 44 | super(NOT, where, Type.tBoolean, right); |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * Select the type of the expression |
| 49 | */ |
| 50 | void selectType(Environment env, Context ctx, int tm) { |
| 51 | right = convert(env, ctx, Type.tBoolean, right); |
| 52 | } |
| 53 | |
| 54 | /* |
| 55 | * Check a "not" expression. |
| 56 | * |
| 57 | * cvars is modified so that |
| 58 | * cvar.vsTrue indicates variables with a known value if |
| 59 | * the expression is true. |
| 60 | * cvars.vsFalse indicates variables with a known value if |
| 61 | * the expression is false |
| 62 | * |
| 63 | * For "not" expressions, we look at the inside expression, and then |
| 64 | * swap true and false. |
| 65 | */ |
| 66 | |
| 67 | public void checkCondition(Environment env, Context ctx, Vset vset, |
| 68 | Hashtable exp, ConditionVars cvars) { |
| 69 | right.checkCondition(env, ctx, vset, exp, cvars); |
| 70 | right = convert(env, ctx, Type.tBoolean, right); |
| 71 | // swap true and false |
| 72 | Vset temp = cvars.vsFalse; |
| 73 | cvars.vsFalse = cvars.vsTrue; |
| 74 | cvars.vsTrue = temp; |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Evaluate |
| 79 | */ |
| 80 | Expression eval(boolean a) { |
| 81 | return new BooleanExpression(where, !a); |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * Simplify |
| 86 | */ |
| 87 | Expression simplify() { |
| 88 | // Check if the expression can be optimized |
| 89 | switch (right.op) { |
| 90 | case NOT: |
| 91 | return ((NotExpression)right).right; |
| 92 | |
| 93 | case EQ: |
| 94 | case NE: |
| 95 | case LT: |
| 96 | case LE: |
| 97 | case GT: |
| 98 | case GE: |
| 99 | break; |
| 100 | |
| 101 | default: |
| 102 | return this; |
| 103 | } |
| 104 | |
| 105 | // Can't negate real comparisons |
| 106 | BinaryExpression bin = (BinaryExpression)right; |
| 107 | if (bin.left.type.inMask(TM_REAL)) { |
| 108 | return this; |
| 109 | } |
| 110 | |
| 111 | // Negate comparison |
| 112 | switch (right.op) { |
| 113 | case EQ: |
| 114 | return new NotEqualExpression(where, bin.left, bin.right); |
| 115 | case NE: |
| 116 | return new EqualExpression(where, bin.left, bin.right); |
| 117 | case LT: |
| 118 | return new GreaterOrEqualExpression(where, bin.left, bin.right); |
| 119 | case LE: |
| 120 | return new GreaterExpression(where, bin.left, bin.right); |
| 121 | case GT: |
| 122 | return new LessOrEqualExpression(where, bin.left, bin.right); |
| 123 | case GE: |
| 124 | return new LessExpression(where, bin.left, bin.right); |
| 125 | } |
| 126 | return this; |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Code |
| 131 | */ |
| 132 | void codeBranch(Environment env, Context ctx, Assembler asm, Label lbl, boolean whenTrue) { |
| 133 | right.codeBranch(env, ctx, asm, lbl, !whenTrue); |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * Instead of relying on the default code generation which uses |
| 138 | * conditional branching, generate a simpler stream using XOR. |
| 139 | */ |
| 140 | public void codeValue(Environment env, Context ctx, Assembler asm) { |
| 141 | right.codeValue(env, ctx, asm); |
| 142 | asm.add(where, opc_ldc, new Integer(1)); |
| 143 | asm.add(where, opc_ixor); |
| 144 | } |
| 145 | |
| 146 | } |